Uruguay's likely next president tried to lead an armed revolution as a young man, hiding in sewers, killing a police officer and twice escaping prison through elaborately dug tunnels.
Polls suggest Jose Mujica _ now 74 and committed to working within the democratic system _ will easily win Sunday, keeping the center-left Broad Front coalition in power.
His rival Luis A. Lacalle, 68, a former president with the center-right National Party, has failed to gain traction with claims that Mujica would transform Uruguay into a radical socialist state.
The current president, Tabare Vazquez, comes from the Socialist Party but he has pursued moderate economic policies during his term, and even Lacalle has acknowledged that the country's European-style social-democracy has helped Uruguay survive the global economic crisis.
Both candidates have said they would maintain economic policies projected to create 1.9 percent growth in gross domestic product for 2009, a year when many other economies have shrunk.
Lacalle would cut taxes, however _ in particular by eliminating a tax on pensions and taking apart a progressive income tax of up to 25 percent _ and he says he would make other moves to reduce the weight of government on private enterprise.
Crime and abortion also became major campaign themes. To combat delinquency, Mujica said he would focus on the root causes of poverty and social marginalization. Lacalle said he would take a harder line, using the Interior Ministry, police and full force of the law against criminals.
And while Lacalle firmly opposes legalizing abortion, Mujica says he will not veto a measure to depenalize it. Lawmakers of his Broad Front pushed through a measure to allow some abortions last year, but Vazquez vetoed it.
Mujica finished first in October's initial round with nearly 48 percent to 29 percent for Lacalle, who was president from 1990-1995. While Lacalle is expected to pick up most supporters of third-place finisher Pedro Bordaberry of the Colorado Party, several polls show Mujica with an advantage of seven to 10 percentage points.
Sunday's winner will begin a five-year term on March 1, 2010.
Lacalle has said Mujica would push the country from a stable democracy toward socialism, and into ideological alliances with presidents Hugo Chavez in Venezuela and Cristina Fernandez in Argentina.
Mujica was a leader of the Tupamaru guerrillas, who were inspired by the Cuban revolution to organize kidnappings, bombings, robberies and other attacks on the conservative but democratically elected governments of the 1960s.
Convicted of killing a policeman in 1971, he endured torture and solitary confinement during nearly 15 years in prison before he was granted amnesty at end of the 1973-1985 dictatorship.
In the quarter-century since then, Mujica helped transform the guerrillas into a legitimate political movement, became the top vote-getter in Congress and served as agriculture minister under Vazquez, whose victory ended decades of center-right rule.
In the spectrum of Latin leaders, Mujica may turn out to be something like Brazil's President Luiz Inacio Lula da Silva, who began as a radical leftist and later realized that more could be done for social justice by working within the system, said Mark Jones, a political scientist and Uruguay expert at Rice University in Texas.
Uruguay's stable, parliamentary democracy tends to thwart radical changes and Mujica, like all Uruguayan presidents, will need to build consensus to get anything done, Jones said.
Associated Press Writer Michael Warren in Buenos Aires contributed to this report.